Yeah that bug in the Column Browser was very annoying! back to normal with 12.6.3
Downgraded both Sierra and High Sierra to iTunes 12.6.3 and tested the App updates / App sync
Updating iTunes once can update all iOS devices afterward without downloading for the same apps again on each device - I turned off wifi and updated phone and ipad to test it - it works!
Also for those interested you can rearrange the pages of apps again from iTunes and install ringtones etc.with iTunes 12.6.3
Downgraded both Sierra and High Sierra to iTunes 12.6.3 and tested the App updates / App sync
Updating iTunes once can update all iOS devices afterward without downloading for the same apps again on each device - I turned off wifi and updated phone and ipad to test it - it works!
Also for those interested you can rearrange the pages of apps again from iTunes and install ringtones etc.with iTunes 12.6.3